Not everyone, because there are the Neutral (don't give a shit about it) and the Haters (people that says it's a girlish cartoon [It's is, but it are more complex than any I saw with my daughter]). And I am a Brony too even my daughter and my son are.
Yeah. When it first started it was cool because boys aren't supposed to like MLP, but now it's common. Like years ago if you liked anime you were a geek and people made fun of you. Now EVERYBODY seems to love it